Description:
------------
The $length parameter of this function is optional in the documentation, but
currently it can't be skipped to only set the case sensitivity flag. Values like
null or false get converted into 0 which causes a warning and the function returns
false.
Using null to skip the $length parameter would be nice.
Test script:
---------------
<?php
// should output: 0
echo substr_compare("hello World", "world", 6, null, true), PHP_EOL;
?>
Expected result:
----------------
0
Actual result:
--------------
Warning: substr_compare(): The length must be greater than zero